1. Field of the Invention
The present invention relates to an optical disc recording/reproducing apparatus that records and reproduces information on and from an optical disc. More particularly, the present invention relates to an optical disc recording/reproducing apparatus capable of displaying the number of times writing has been performed to a DVD+RW optical disc.
2. Description of Related Art
In recent years, DVDs (digital versatile discs), which are optical discs that can record information such as a large amount of video/audio data like that of movies, have been increasingly widespread. As these DVDs, various types are known such as a DVD−ROM containing information that is pre-recorded by a manufacturer and cannot be rewritten by a user, a DVD−R or a DVD+R that allows the user to record information thereon only once, and a DVD−RW, a DVD+RW, or a DVD−RAM that allows the user to rewrite information thereon a specified number of times. Information recorded on these DVDs can be reproduced by optical disc reproducing apparatuses (DVD players) or optical disc recording/reproducing apparatuses (DVD recorders), and information can be recorded on a DVD−R, a DVD+R, a DVD−RW, a DVD+RW, and a DVD−RAM by using optical disc recording/reproducing apparatuses.
Incidentally, if information of a rewritable optical disc such as a DVD−RW, a DVD+RW, or a DVD−RAM is rewritten over and over again, residual components are increased due to various causes such as deterioration in characteristics of medium materials themselves or tracking deviation, resulting in degradation of recording quality. In the aforementioned rewritable optical disc, a phase change recording method is adopted that exploits transformation between an amorphous state and a crystalline state. Thus, deterioration in characteristics of materials themselves inevitably sets a limit on the number of times the disc can be rewritten. If the users carry out rewrite operation without knowing they are violating the limit or approaching it, an S/N ratio of a sector to which writing has been performed deteriorates greatly, or crosstalk into the adjacent tracks increases. This undesirably degrades recording quality.
To solve this problem, a conventional optical disc recording/reproducing apparatus is proposed that simply measures, for example, an error rate of a loaded optical disc and causes a display device to display the error rate thus measured. However, the number of times a rewritable optical disc has been rewritten is not displayed thereon, making it impossible for the user to know how long a medium lasts or when it needs replacing. This causes inconvenience for the user.
Another conventional technique disclosed in JP-A-H02-018714 records the number of times an optical disc has been rewritten, and, if the number thus recorded exceeds a specified number, lights an indication lamp. However, this technique does not inform how long a medium lasts or when it needs replacing by displaying the number of times a rewritable optical disc has been rewritten.
Still another conventional technique disclosed in JP-A-H04-216322 records the number of times a sector on an optical disc has been rewritten, then compares the number thus recorded with a specified number and then, if the former exceeds the latter, performs recording in another sector. However, this conventional technique also does not inform how long a medium lasts or when it needs replacing by displaying the number of times a rewritable optical disc has been rewritten.
Still another conventional technique disclosed in JP-A-2001-350596 records the number of times writing has been performed to a recording apparatus, and, if the number thus recorded exceeds a specified value, produces a signal. However, this recording apparatus is a hard disk device. Thus, this conventional technique does not inform how long a medium lasts or when it needs replacing by displaying the number of times a rewritable optical disc has been rewritten.
Still another conventional technique disclosed in JP-A-H09-035466 keeps count of the number of recording operations on a tape, and, if the number thus counted exceeds a limit value, generates an alarm. However, this conventional technique does not inform how long a medium lasts or when it needs replacing by displaying the number of times a rewritable optical disc has been rewritten.
Still another conventional technique disclosed in JP-A-H08-221949 keeps count of the number of times data has been written to or deleted from a magneto-optical disc, and, if the number thus counted exceeds a predetermined value, generates an alarm. However, this conventional technique does not inform how long a medium lasts or when it needs replacing by displaying the number of times a rewritable optical disc has been rewritten.
In view of the conventionally experienced problems described above, it is an object of the present invention to provide an optical disc recording/reproducing apparatus that can inform the user how long a medium (optical disc) lasts or when it needs replacing by displaying the number of times writing has been performed to a rewritable optical disc (especially a DVD+RW optical disc).